A population-based case-control study of Selective Serotonin Reuptake Inhibitors (SSRIs) and breast cancer: the impact of duration of use, cumulative dose and latency

Beyond Psychotropic: Potential Repurposing of Fluoxetine toward Cancer Therapy

Drug repurposing, rebranding an existing drug for a new therapeutic indication, is deemed a beneficial approach for a quick and cost-effective drug discovery process by skipping preclinical, Phase 1 trials and pharmacokinetic studies. Several psychotropic drugs, including selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs), were studied for their potential application in different diseases, especially in cancer therapy. Fluoxetine (FLX) is one of the most prescribed psychotropic agents from the SSRIs class for the treatment of several neuropsychiatric disorders with a favorable safety profile. FLX exhibited different oncolytic effects via mechanisms distinct from its main serotonergic activity. Taking advantage of its ability to rapidly penetrate the blood-brain barrier, FLX could be particularly useful in brain tumors. This was proved by different in vitro and in vivo experiments using FLX as a monotherapy or combination with temozolomide (TMZ) or radiotherapy. In this review of the literature, we summarize the potential pleiotropic oncolytic roles of FLX against different cancers, highlighting the multifaceted activities of FLX and its ability to interrupt cancer proliferation via several molecular mechanisms and even surmount multidrug resistance (MDR). We elaborated on the successful synergistic combinations such as FXR/temozolomide and FXR/raloxifene for the treatment of glioblastoma and breast cancer, respectively. We showcased beneficial pharmaceutical trials to load FLX onto carriers to enhance its safety and efficacy on cancer cells. This is the first review article extensively summarizing all previous FLX repurposing studies for the management of cancer.

Sertraline inhibits stress-induced tumor growth through regulating CD8+ T cell-mediated anti-tumor immunity

Chronic stress has been reported to be associated with tumor initiation and progression. But the underlying mechanism and the specific role of tumor immunity in this process are still unknown. Herein, we applied the repeated restrain stress model in C57BL/6J mice and found that the tumor growth in stressed mice was accelerated compared with that in control mice. In addition, serotonin, also called 5-hydroxytryptamine (5-HT), in the serum of stressed mice was also elevated. Sertraline, a selective serotonin reuptake inhibitor used in the clinic, can restore the serum 5-HT level in stressed mice and restrain tumor growth. We further explored the distribution of major immune cells, including B lymphocytes cells, T lymphocytes, natural killer cells, dendritic cells, tumor-associated macrophages (TAM) and regulatory T cells (Treg). We found that the infiltration of CD8+ T cells in the tumor microenvironment (TME) decreased significantly in stressed mice. And the extra 5-HT treatment could further decrease the infiltration of CD8+ T cells in the TME. The expression of IFN-γ and Granular enzyme B (GzmB) in CD8+ T cells were also dropped in the stressed mice group, whereas the expression of programmed cell death protein 1 (PD-1) on CD8+ T cells was increased. The T cell deficiency induced by stress can be reversed by sertraline, indicating its promising role in strengthening the efficacy of anti-PDL1/PD-1 immunotherapy. The present study provides new mechanistic insights into the impact of chronic stress on antitumor immunity and implicates a novel combined immunotherapy strategy for cancer patients with chronic stress.

Selective serotonin reuptake inhibitor use and the risk of hepatocellular carcinoma: a systematic review and dose-response analysis of cohort studies with one million participants

PURPOSE

Recent studies have suggested a lower risk of hepatocellular carcinoma (HCC) in patients receiving selective serotonin reuptake inhibitors (SSRIs). The current study aimed to provide an updated and comprehensive assessment of the association between SSRI use and development of HCC.

METHODS

This is a systematic review and meta-analysis of all observational studies published until June 2021. We comprehensively searched PubMed/Medline, Web of Science, and Embase to identify studies comparing SSRIs use with control in relation to the risk of HCC. We calculated pooled relative risks (RRs) and 95% confidence intervals (CIs) for the association between SSRI use and incident HCC risk using random-effects meta-analysis. A dose-response analysis was conducted to evaluate the HCC risk according to the defined daily dose (DDD) of SSRI use.

RESULTS

Eight observational studies, comprising 1,051,096 participants and 22,316 incidences of HCC, examining the association between SSRIs use and HCC risk, were included in the systematic review (adjusted RR: 0.66; 95% CI: 0.56-0.79; P ≤ 0.001). In subgroup analysis, the magnitude of benefit associated with SSRIs was significantly higher in patients with hepatitis infection (RR: 0.70, 95% CI: 0.51-0.95) than the general population (P_{heterogeneity} = 0.700). The dose-response analysis indicated strong inverse association between cumulative DDD of SSRI and risk of HCC (coefficient: - 0.0030; P = 0.002; R² = 0.78).

CONCLUSIONS

The results of this review show that SSRI use was associated with a 34% lower risk of HCC, which tend to be dose dependent. Further prospective studies are warranted to confirm these observations across the spectrum of chronic liver disease and hepatitis infection.

Relationship between antidepressive agents and incidence risk of breast cancer: systematic review and meta-analysis

Purpose: This study aimed to review the association between antidepressive agent (AD) use and the incidence risk of breast cancer. Methods: CBM, WOS, Embase, PubMed and Cochrane Library were systematically searched in July 2019. The methodological quality of the studies was assessed through the Newcastle-Ottawa Scale. Results: We included 19 studies from six countries or regions with relationships between breast cancer and ADs. Subgroup analysis showed no significant association in nested case-control or case-control studies; however, cohort studies revealed a significant association (odds ratio = 1.11; 95% CI: 1.04-1.17). Conclusions: This meta-analysis indicates that breast cancer was not associated with the use of ADs when considering all types of studies, but an association was observed if we considered cohort studies.

High content phenotypic screening identifies serotonin receptor modulators with selective activity upon breast cancer cell cycle and cytokine signaling pathways

Heterogeneity in disease mechanisms between genetically distinct patients contributes to high attrition rates in late stage clinical drug development. New personalized medicine strategies aim to identify predictive biomarkers which stratify patients most likely to respond to a particular therapy. However, for complex multifactorial diseases not characterized by a single genetic driver, empirical approaches to identifying predictive biomarkers and the most promising therapies for personalized medicine are required. In vitro pharmacogenomics seeks to correlate in vitro drug sensitivity testing across panels of genetically distinct cell models with genomic, gene expression or proteomic data to identify predictive biomarkers of drug response. However, the vast majority of in vitro pharmacogenomic studies performed to date are limited to dose-response screening upon a single viability assay endpoint. In this article we describe the application of multiparametric high content phenotypic screening and the theta comparative cell scoring method to quantify and rank compound hits, screened at a single concentration, which induce a broad variety of divergent phenotypic responses between distinct breast cancer cell lines. High content screening followed by transcriptomic pathway analysis identified serotonin receptor modulators which display selective activity upon breast cancer cell cycle and cytokine signaling pathways correlating with inhibition of cell growth and survival. These methods describe a new evidence-led approach to rapidly identify compounds which display distinct response between different cell types. The results presented also warrant further investigation of the selective activity of serotonin receptor modulators upon breast cancer cell growth and survival as a potential drug repurposing opportunity.

Ion Channel and Neurotransmitter Modulators as Electroceutical Approaches to the Control of Cancer

The activities of individual cells must be tightly coordinated in order to build and maintain complex 3-dimensional body structures during embryogenesis and regeneration. Thus, one way to view cancer is within systems biology as a network disorder affecting the ability of cells to properly interact with a morphodynamic field of instructive signals that keeps proliferation and migration orchestrated toward the anatomical needs of the host or-ganism. One layer of this set of instructive microenvironmental cues is bioelectrical. Voltage gradients among all somatic cells (not just excitable nerve and muscle) control cell behavior, and the ionic coupling of cells into networks via electrochemical synapses allows them to implement tissue-level patterning decisions. These gradients have been increasingly impli-cated in the induction and suppression of tumorigenesis and metastasis, in the emerging links between developmental bioelectricity to the cancer problem. Consistent with the well-known role of neurotransmitter molecules in transducing electrical activity to downstream cascades in the brain, serotonergic signaling has likewise been implicated in cancer. Here, we review these recent data and propose new approaches for manipulating bioelectric and neurotransmitter pathways in cancer biology based on a bioelectric view of cancer. To sup-port this methodology, we present new data on the effects of the SSRI Prozac and its analog (ZINC ID = ZINC06811610) on survival of both cancer (MCF7) and normal (MCF10A) breast cells exposed to these compounds. We found an IC50 concentration (25 μM for Pro-zac and 100 μM for the Prozac analog) at which these compounds inhibited tumor cell sur-vival and proliferation. Additionally, at these concentrations, we did not observe alterations in a non-tumoral cell line. This constitutes a proof-of-concept demonstration for our hy-pothesis that the use of both existing and novel drugs as electroceuticals could serve as an alternative to highly toxic chemotherapy strategies replacing or augmenting them with less toxic alternatives. We believe this new approach forms an exciting roadmap for future bio-medical advances.

Serotonin transporter antagonists target tumor-initiating cells in a transgenic mouse model of breast cancer

Accumulating data suggests that the initiation and progression of human breast tumors is fueled by a rare subpopulation of tumor cells, termed breast tumor-initiating cells (BTIC), which resist radiotherapy and chemotherapy. Consequently, therapies that abrogate BTIC activity are needed to achieve durable cures for breast cancer patients. To identify such therapies we used a sensitive assay to complete a high-throughput screen of small molecules, including approved drugs, with BTIC-rich mouse mammary tumor cell populations. We found that inhibitors of the serotonin reuptake transporter (SERT) and serotonin receptors, which include approved drugs used to treat mood disorders, were potent inhibitors of mouse BTIC activity as determined by functional sphere-forming assays and the initiation of tumor formation by transplant of drug-exposed tumor cells into syngeneic mice. Moreover, sertraline (Zoloft), a selective serotonin reuptake inhibitor (SSRI), synergized with docetaxel (Taxotere) to shrink mouse breast tumors in vivo. Hence drugs targeting the serotonergic system might be repurposed to treat breast cancer patients to afford more durable breast cancer remissions.

Antidepressant medication use and nasopharyngeal cancer risk: a nationwide population-based study

BACKGROUND

The association between antidepressant exposure and nasopharyngeal cancer (NPC) has not been previously explored. The purpose of this study was to investigate the association between antidepressant prescription, including novel antidepressants, and the risk of NPC in a population-based study.

MATERIALS AND METHODS

Data for the analysis were derived from National Health Insurance Research Database. We identified 16,957 cases with a diagnosis of NPC and 83,231 matched controls by using a nested case-control design. A conditional logistic regression model was used, with adjustments for potentially confounding variables (eg, comorbid physical diseases, comorbid psychiatric diseases, and other medications).

RESULTS

We report no association between NPC incidence and antidepressant prescription. For all classes of antidepressants, antidepressant exposure, regardless of cumulative dose, had no significant effect on NPC incidence (adjusted odds ratio of cumulative selective serotonin reuptake inhibitor exposure ≥336 defined daily dose was 1.18 [95% CI: 0.90-1.53]; tricyclic antidepressant exposure ≥336 defined daily dose was 1.18 [95% CI: 0.80-1.74]).

CONCLUSION

There was no association between antidepressant prescription and incident NPC.

Depression, Antidepressant Use, and Breast Cancer Risk in Pre- and Postmenopausal Women: A Prospective Cohort Study

Background: Depression and antidepressant use is highly prevalent among U.S. women and may be related to increased breast cancer risk. However, prior studies are not in agreement regarding an increase in risk.Methods: We conducted a prospective cohort study within the Nurses' Health Study (NHS) and NHSII among females age 25 and older. Over more than 10 years of follow-up in each cohort, 4,014 incident invasive breast cancers were diagnosed. We used Cox proportional hazards regressions with updating of exposures and covariates throughout follow-up to estimate HRs and 95% confidence intervals (CIs) for associations between clinical depression and antidepressant use with invasive breast cancer risk. Analyses were repeated separately for in situ disease, as well as stratified by estrogen receptor (ER) subtype and menopausal status at diagnosis.Results: No statistically significant associations were observed between clinical depression (HR for reporting ≥3 times vs. 0, 1.13; 95% CI, 0.85-1.49) or antidepressant use (HR for reporting ≥3 times vs. 0, 0.92; 95% CI, 0.80-1.05) and invasive breast cancer risk in multivariable analyses. Likewise, we observed no significant associations between clinical depression or antidepressant use and risk of in situ, ER⁺, ER^-, premenopausal, or postmenopausal breast cancer.Conclusions: In the largest prospective study to date, we find no evidence that either depression or antidepressant use increase risk of breast cancer.Impact: The results of this study are reassuring in that neither depression nor antidepressant use appear to be related to subsequent breast cancer risk. Cancer Epidemiol Biomarkers Prev; 27(3); 306-14. ©2017 AACR.

Antidepressants in association with reducing risk of oral cancer occurrence: a nationwide population-based cohort and nested case-control studies

Objectives

Several studies suggested that antidepressant use may increase or decrease the risk of cancer occurrence, depending on specific cancer types. The possible carcinogenic effect of antidepressants has received substantial attention; however, evidence remains inconclusive. Here we investigated associations between the use of antidepressants and occurrences of oral cancer (OC).

Methods

Two million samples were randomly collected from the National Health Insurance Research Database in Taiwan, which covers 98% of the total population (23 million). All patients from2000 to 2009 were followed up. We identified 5103 patients newly diagnosed with OC after antidepressants use in addition to 20,412 non-OC matched subjects and 95,452 unmatched non-OC subjects.

Results

In nested case control analysis, factors associating with OC, including age [OR = 1.02; 95% confidence interval (CI) = 1.01–1.03) and male (OR = 5.30; 95% CI = 4.92–5.70) were independently associated with increased risk of OC. Based on the functions of antidepressants, antidepressants treatment medications were further classified to investigate risk of OC. Selective serotonin reuptake inhibitors (OR = 0.61; 95% CI = 0.53–0.70) and tricyclic antidepressants (OR = 0.57; 95% CI = 0.52–0.63) were associated with reduced risk of OC. The risk of developing OC among subjects taking antidepressants was less than 26% [hazard ratio (HR) =0.74; 95% CI = 0.68–0.81] in prospective cohort study. The effect of a cumulative duration and dose was a significantly reduced risk of OC.

Conclusions

The association between antidepressant use and decreasing OC risk were demonstrated by both prospective and nested case–control studies.

SSRIs associated with decreased risk of hepatocellular carcinoma: A population-based case-control study

BACKGROUND

Hepatocellular carcinoma (HCC) is the second leading cancer-related cause of mortality worldwide. Antidepressants, especially selective serotonin reuptake inhibitors (SSRIs), are commonly used worldwide. Available evidence investigating the association between SSRIs use and HCC risk is limited.

OBJECTIVE

The present study aimed to investigate if the effect of all kinds of SSRIs on HCC was the same or not using population-based study.

METHODS

The nationwide population-based study herein using Taiwan's National Health Insurance Research Database included a total of 59 859 cases with HCC and 285 124 matched controls. Conditional logistic regression analyses were adjusted for confounding variables.

RESULTS

All common kinds of SSRIs including fluoxetine, sertraline, paroxetine, citalopram, escitalopram, and fluvoxamine were associated with lower HCC risk, and the findings were dose-dependent (eg, fluoxetine: 1-28 DDD [defined daily dose]: adjusted odds ratio [aOR]: 0.81, 95% confidence interval [CI], 0.73-0.89; 29-365 DDD: aOR: 0.71, 95% CI, 0.64-0.79; and ≥366 DDD: aOR: 0.55, 95% CI, 0.45-0.67) (P for trend < .001).

CONCLUSIONS

All kinds of SSRIs were associated with decreased risk of HCC.

Depression, Antidepressant Use, and Postmenopausal Breast Cancer Risk

BACKGROUND

Whether depression and antidepressant (AD) use might influence breast cancer risk is unclear, and these exposures have not been evaluated together in a single, prospective cohort study of breast cancer risk.

METHODS

Among 71,439 postmenopausal women in the Women's Health Initiative Observational Study (WHI-OS), we estimated multivariable-adjusted HRs for the independent and joint effects of depressive symptoms and AD use on breast cancer risk using Cox proportional hazards regression.

RESULTS

When analyzed separately, neither depressive symptoms nor AD use at baseline were associated with a significantly increased risk of total breast cancer (HR = 0.96, 95% CI, 0.85-1.08; HR = 1.04, 95% CI, 0.92-1.20, respectively) or invasive breast cancer (HR = 0.98, 95% CI, 0.86-1.12; HR = 1.00, 95% CI, 0.86-1.16, respectively). Current AD use was associated with a borderline-significant increase of in situ breast cancer (HR = 1.30, 95% CI, 0.99-1.75) after adjustment for depressive symptoms; however, this relationship was attenuated after adjustment for mammographic screening (HR = 1.08, 95% CI, 0.76-1.51). No significant variation in total breast cancer risk was observed when the separate and joint effects of depressive symptoms and AD use were explored (P for interaction = 0.14).

CONCLUSION

We found no evidence that either depression or AD use influences breast cancer risk. An elevated risk of in situ disease among AD users could not be ruled out, though is likely due to increased screening in this subgroup.

IMPACT

Given the high prevalence of these exposures, these results may provide reassurance to the millions of women who are depressed and/or use ADs each year.

Anti-depressant therapy and cancer risk: a nested case-control study

Previous studies demonstrated a possible association between anti-depressant therapy with selective serotonin reuptake inhibitors (SSRI) and tricyclic anti-depressants (TCA), several genetic and hormonal pathways and cancer risk, with inconsistent results. Exposure to serotonin-norepinephrine reuptake inhibitors (SNRI) was not studied extensively. We sought to evaluate the association between exposure to SSRIs, TCAs and SNRIs and the five most common solid tumors. We conducted nested case-control studies using a large UK population-representative database. Cases were those with any medical code for the specific malignancy. For every case, four controls matched on age, sex, practice site, and duration of follow-up before index date were selected using incidence-density sampling. Exposure of interest was SSRI, SNRI or TCA therapy before index date. Odds ratios (ORs) and 95% CIs were estimated for each anti-depressant class using conditional logistic-regression analysis, adjusted for potential confounders, such as obesity, smoking history and alcohol consumption.

RESULTS

109,096 cancer patients and 426,402 matched controls were included. Current SSRI users with treatment initiation>one year before index date had modestly higher risk for lung and breast cancers with ORs of 1.27 (95% CI 1.16-1.38) and 1.12 (95% CI 1.06-1.18), respectively. Among current TCA users, there was a higher risk only for lung cancers with OR of 1.45 (95% CI 1.31-1.6). There was no statistically significant association between current SNRI therapy and cancer risk.

DISCUSSION

Treatment with SSRI and TCA might be associated with increased lung cancer risk. SSRI therapy might be associated with modest increase in breast cancer risk.

Is amisulpride safe when prescribed to breast and prostate cancer patients?

In the last decades, the potential association between antidepressants and cancer risk has been increasingly investigated. Fundamental researches, performed on animal models and cell tumoral lines, have highlighted several biological mechanisms possibly supporting this association. Nevertheless, the epidemiological studies investigating the risk of cancer in patients receiving selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) have provided conflicting and inconclusive results. Therefore, the prescription of several antidepressants in oncologic patients still remains a matter of discussion. The aim of this review is to present and discuss available evidence concerning the association between the risk of breast and prostate cancer and the use of antidepressant medications. Thus, consistencies, differences, and contradictions of available data are reported. A special focus is addressed to amisulpiride, a widely prescribed drug still poorly investigated with regard to the risk of cancer occurrence and recurrence. Overall, there is no definitive evidence of increased risk of breast and prostate cancer among patients exposed to SSRIs and TCAs. The association between amisulpiride and cancer risk has been to date scarcely explored and considered in clinical settings. Nevertheless, the hyperprolactinemia frequently resulting from its adoption has been repeatedly associated, to increased cancer risk and poorer prognosis in cancer patients. Thus, the use of amisulpiride among cancer patients should be carefully considered.

Antidepressants: influence on cancer and immunity?

Two decades ago, it was hypothesized that antidepressants could alter the course of neoplastic diseases. However, contradictory findings indicated that antidepressants could either have carcinogenic properties or improve the disease outcome. Intriguingly, controversial results were reported on the action of antidepressant drugs on immune function. Further hypotheses proposed that antidepressants could indirectly affect the cancer prognosis through the modulation of antitumor activity. Here we review the literature in order to elucidate the influence of antidepressants on cancer and immunity.

Selective Serotonin Reuptake Inhibitor (SSRI) Antidepressants, Prolactin and Breast Cancer

Selective serotonin reuptake inhibitors (SSRIs) are a widely prescribed class of antidepressants. Laboratory and epidemiologic evidence suggests that a prolactin-mediated mechanism secondary to increased serotonin levels at neuronal synapses could lead to a potentially carcinogenic effect of SSRIs. In this population-based case-control study, we evaluated the association between SSRI use and breast cancer risk as a function of their relative degree of inhibition of serotonin reuptake as a proxy for their impact on prolactin levels. Cases were 2,129 women with primary invasive breast cancer diagnosed from 2003 to 2007, and controls were 21,297 women randomly selected from the population registry. Detailed information for each SSRI prescription dispensed was compiled using the Saskatchewan prescription database. Logistic regression was used to evaluate the impact of use of high and lower inhibitors of serotonin reuptake and duration of use, as well as to assess the effect of individual high inhibitors on the risk of breast cancer. Exclusive users of high or lower inhibitors of serotonin reuptake were not at increased risk for breast cancer compared with non-users of SSRIs (OR = 1.01, CI = 0.88–1.17 and OR = 0.91, CI = 0.67–1.25 respectively), regardless of their duration of use or menopausal status. While we cannot rule out the possibility of a clinically important risk increase (OR = 1.83, CI = 0.99–3.40) for long-term users of sertraline (≥24 prescriptions), given the small number of exposed cases (n = 12), the borderline statistical significance, and the wide confidence interval, these results need to be interpreted cautiously. In this large population-based case-control study, we found no conclusive evidence of breast cancer risk associated with the use of SSRIs even after assessing the degree of serotonin reuptake inhibition and duration of use. Our results do not support the serotonin-mediated pathway for the prolactin-breast cancer hypothesis.

Use of antidepressants and the risk of breast cancer: a meta-analysis

The goal of this study was to perform a meta-analysis to examine the association between the use of antidepressants (AD) and the risk of breast cancer. We searched the EMBASE and MEDLINE databases from inception through February 25, 2012, using search terms related to ADs and breast cancer. Two evaluators independently reviewed and selected articles and extracted data based on predetermined selection criteria. Pooled effect estimates were obtained by using random- and fixed effects meta-analyses. Of the 3,209 titles identified, 18 articles met the inclusion criteria. The overall risk of breast cancer did not increase among AD users [adjusted odds ratio (aOR) 1.02; 95 % CI 0.96-1.08]. Those who took tricyclic antidepressants (TCAs) or selective serotonin reuptake inhibitors (SSRIs) were not at increased risks of breast cancer. In subgroup meta-analyses, null associations were consistent across the type of AD, funding sources, the number of adjusted variables, medication dose, the ascertainment of exposure, and methodological quality. In subgroup analyses based on exposure duration, a marginal association was observed for the use of SSRIs < 1-2 years (aOR 1.10; 95 % CI 1.02-1.19). However, this effect was attenuated over time and those using SSRIs for more than 1-2 years had no elevated breast cancer risk. These results support the lack of a clinically meaningful association between AD use and the development of breast cancer and provide considerable reassurance. Given that the data collected to date do not support changing the current prescribing patterns for ADs, the important benefits of AD therapy must be considered.

Comparing the cohort design and the nested case-control design in the presence of both time-invariant and time-dependent treatment and competing risks: bias and precision

Purpose

Observational studies using electronic administrative healthcare databases are often used to estimate the effects of treatments and exposures. Traditionally, a cohort design has been used to estimate these effects, but increasingly, studies are using a nested case–control (NCC) design. The relative statistical efficiency of these two designs has not been examined in detail.

Methods

We used Monte Carlo simulations to compare these two designs in terms of the bias and precision of effect estimates. We examined three different settings: (A) treatment occurred at baseline, and there was a single outcome of interest; (B) treatment was time varying, and there was a single outcome; and C treatment occurred at baseline, and there was a secondary event that competed with the primary event of interest. Comparisons were made of percentage bias, length of 95% confidence interval, and mean squared error (MSE) as a combined measure of bias and precision.

Results

In Setting A, bias was similar between designs, but the cohort design was more precise and had a lower MSE in all scenarios. In Settings B and C, the cohort design was more precise and had a lower MSE in all scenarios. In both Settings B and C, the NCC design tended to result in estimates with greater bias compared with the cohort design.

Conclusions

We conclude that in a range of settings and scenarios, the cohort design is superior in terms of precision and MSE. Copyright © 2012 John Wiley & Sons, Ltd.